Dioscorea polystachya Rhizome

Dioscorea polystachya Rhizome

Proposed For Development Version 0.1

Dioscorea polystachya Rhizome


 

DEFINITION

The article consists of the dried rhizomes of Dioscorea polystachya Turcz. (Family Dioscoreaceae) from which fibrous roots and periderm have been removed. It is collected in winter after the leaves and stems have withered. It meets the Acceptance criteria under the Assay.

 

SYNONYMS

Dioscorea batatas Decne.

Dioscorea decaisneana Carrière

Dioscorea doryphora Hance

Dioscorea potaninii Prain et Burkill

Dioscorea pseudobatatas (Hauman) Herter

Dioscorea rosthornii Diels

Dioscorea swinhoei Rolfe

 

POTENTIAL CONFOUNDING MATERIALS

 

SELECTED COMMON NAMES

Chinese: 山葯, 薯蕷

Danish:  Kinayams

English: Chinese yam, Chinese-potato, cinnamon vine, cinnamon yam, common yam, Japanese yam, long Chinese yam

French: Igname de Chine

German: Chinesische Yams, Chinesische Yamswurzel, Echte Yamswurzel, Japanische Berg-Yams, koreanische Yams

Japanese: Sanyaku 

Korean:  마

Malay: Ubi (Indonesia)

Pinyin: Shan yao, Shu yu

Polish: Pochrzyn chinski

Russian: Ямс китайский

 

CONSTITUENTS OF INTEREST

Steroidal saponins and sapogenins: Dioscin, diosgenin, yamogenin, togogenein, β-sitosterol

 

IDENTIFICATION

• A Botanic Characteristics

Macroscopic: Sub-cylindrical, curved and somewhat flattened, 15–30 cm long, 1.5–6 cm in diameter. The surface is yellowish-white or pale yellow with longitudinal furrows and wrinkles, and fibrous root scars, occasional patches of brownish cork. The texture is compact and not easily broken. The fracture is white and starchy.

Microscopic: (To Come)

• B. Thin-Layer Chromatography

Standard solution A: 1.0 mg/mL of USP Diosgenin RS  (to come) in methanol

Standard solution B: Sonicate about 1.0 g of USP Powdered Dioscorea polystachya Rhizome RS (to come) in 50 mL of methanol at 60° for 30 min. Filter the extract, evaporate to dryness, dissolve in 20 mL of 3M hydrochloric acid solution, and heat in a water bath for 30 min. Cool, add 20 mL dichloromethane, and reflux for 15 min. Cool, separate the dichloromethane layer, and evaporate to dryness. Reconstitute the extract in 2.5 mL methanol.

Sample solution: Use 1.0 g of Dioscorea polystachya Rhizome, finely powdered, and prepare as in Standard solution B.

Chromatographic system 

(See Chromatography <621>, Thin-Layer Chromatography.)

Adsorbent: Chromatographic silica gel mixture with an average particle size of 5 µm (HPTLC plates)

Application volume: 10 µL, as 8-mm bands

Relative humidity: Condition the plate to a relative humidity of about 30% using a suitable device.

Developing solvent system: Toluene and acetone (9:1)

Developing distance: 6 cm

Derivatization reagent: Anisaldehyde reagent – 85 mL of ice-cooled methanol mixed with 10 mL glacial acetic acid, 5 mL of sulfuric acid, and 0.5 mL of p-anisaldehyde.

Analysis

Samples: Standard solution A, Standard solution B, and Sample solution

Apply the Samples as bands to a suitable HPTLC plate and dry in air. Develop the chromatograms in a saturated chamber, remove the plate from the chamber, and dry. Treat with Derivatization reagent, and heat for  3 min at 100°. Examine under visible light and UV light at 365 nm.

System suitability: Under visible light, the chromatogram of Standard solution B exhibits a faint brown band at an RF corresponding to the intense diosgenin band in the chromatogram of Standard solution A. Other bands observed in the chromatogram of Standard solution B include a blue band at an RF right above that of the diosgenin band and two faint violet bands near the solvent front. A violet band may also be seen below the diosgenin band.

Under UV light at 365 nm, the chromatogram of Standard solution B exhibits a faint bluish-green band at an RF corresponding to the intense bluish-green diosgenin band in the chromatogram of Standard solution A. Other bands observed in the chromatogram of Standard solution B include a blue band at an RF right above that of the diosgenin band and two faint violet bands near the solvent front. A bluish-violet band may also be seen below the diosgenin band.

Acceptance criteria: Under visible light, the chromatogram of the Sample solution exhibits a faint brown band corresponding in color and RF to the intense brown band in the chromatogram of Standard solution A, and the following bands corresponding to similar bands in the chromatogram of Standard solution B: a blue band at an RF above that of the diogenin band and two violet bands close to the solvent front.

Under UV light at 365 nm, the chromatogram of the Sample solution exhibits a faint bluish-green band corresponding in color and RF to the intense bluish-green band due to diosgenin in the chromatogram of Standard solution A, and the following bands corresponding to similar bands in the chromatogram of Standard solution B: a blue band at an RF above that of the diosgenin band and two violet bands close to the solvent front.

 

ASSAY

Content of Constituents of Interest

CALL FOR SUBMISSION OF VALIDATED INFORMATION

 

Additional information including validation data will be required to complete the development of the Assay. For requirements, please see under "Composition" and related sections of the guidelines document “Monographs in the Herbal Medicines Compendium” at http://hmc.usp.org/about/general-noticesresources.

 

Interested parties are encouraged to submit their proposals to complete the monograph.

 

CONTAMINANTS

Elemental Impurities—Procedures <233>

 Acceptance criteria

Arsenic: NMT 2 µg/g

Cadmium: NMT 0.3 µg/g

Lead: NMT 5 µg/g

Mercury: NMT 0.2 µg/g

Articles of Botanical Origin, General Method for Pesticide Residues Analysis <561>: Meets the requirements

Microbial Enumeration Tests <61>: The total aerobic bacterial count does not exceed 105 cfu/g, the total combined molds and yeasts count does not exceed 103 cfu/g, and the bile-tolerant Gram-negative bacteria does not exceed 103 cfu/g.

Tests for Specified Microorganisms <62>: Meets the requirements of the tests for the absence of Salmonella species and Escherichia coli

Articles of Botanical Origin, Test for Aflatoxins <561>: Meets the requirements

 

SPECIFIC TESTS

Articles of Botanical Origin, Foreign Organic Matter <561>: NMT 2.0%

Articles of Botanical Origin, Water-Soluble Extractives, Method 1 <561>: NLT 7.0%

Loss on Drying <731>

Analysis: Dry 1.0 g of Dioscorea polystachya Rhizome, finely powdered, at 105° for 5 h.

Acceptance criteria: NMT 12.0%

Articles of Botanical Origin, Total Ash <561>

Analysis: 2.0 g of Dioscorea polystachya Rhizome, finely powdered

Acceptance criteria: NMT 4.0%

 

ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers, protected from light and moisture, and store at room temperature.

Labeling: The label states the Latin binomial and the part of the plant contained in the article.

USP Reference Standards <11>

USP Aflatoxins RS

USP Diosgenin RS (to come)

USP Powdered Dioscorea polystachya Rhizome RS (to come)

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